Question

For each of the following predict the sign of ΔS for the process. Question Correct Match Selected Match

O2(g) → O2(l) Correct ΔS(−) ΔS(−)

2NO(g) + O2(g) → 2 N2O(g) Correct ΔS(−) ΔS(−)

NaBr(s) → Na+(aq) + Cl−(aq) Correct ΔS(+) ΔS(+)

NH4Cl(s) → NH3(g) + HCl(g) Correct ΔS(+) ΔS(+)

Please explain why and how delta s is positive and negative for the above answers.

Answer 1

entropy of gas > entropy of aqueous > entropy of liquid > entropy of solid

1)

There are more gases on reactant side.

So, entropy of product is less than reactant.

Entropy is decreasing.

So, delta S is negative

2)

There are more gases on reactant side.

So, entropy of product is less than reactant.

Entropy is decreasing.

So, delta S is negative

3)

There are aqueous on product and solid on reactant side.

Aqueous have more entropy than solid

So, entropy of product is more than reactant.

Entropy is increasing.

So, delta S is positive

4)

There are more gases on product side.

So, entropy of product is more than reactant.

Entropy is increasing.

So, delta S is positive